To generate this list, the team at College Rank looked at hundreds of college arboretums from around the country. Arboretums harbor lavish collections of plants, flowers for visitors and students to enjoy. Arboretums also foster educational and conservation efforts put forth by the university. In generating this ranking, we scored criteria based on total size or acreage of the arboretum, educational resources and community outreach programming, various collections that the arboretum maintains and a total number of species that the arboretum boasts.